Marking 79 years since the largest single attack mounted by a foreign power on Australian soil, the bombing of Darwin Ceremony, 2021 features a reenactment of that day. The "First Post" call signals the start of the duty officer's inspection of a British Army camp's sentry posts, sounding a call at each one. The "Last Post" call originally signalled merely that the final sentry post had been inspected, and the camp was secure for the night. In addition to its normal garrison use, the "Last Post" call had another function at the close of a day of battle. It signalled to those who were still out and wounded or separated that the fighting was done, and to follow the sound of the call to find safety and rest. Its use in Remembrance Day ceremonies in Commonwealth nations has two generally unexpressed purposes: the first is an implied summoning of the spirits of the Fallen to the cenotaph, the second is to symbolically end the day, so that the period of silence before the "Rouse" is blown becomes in effect a ritualised night vigil. The "Last Post" as played at the end of inspection typically lasted for about 45 seconds; when played ceremonially with notes held for longer, pauses extended, and the expression mournful, typical duration could be 75 seconds or more.